Hello people I was wanting a little help, I plan on building a drag car using fords 6 cyl and would like to know how much hp i wood be looking at if i wanted to send the car (mark 4 or 5 cortina) down the strip in 9 sec or 8 would be great, i was thinking a twin turbo setup but im not sure of the advantages disadvantages of a twin and single turbo setup.

twin turbo gives you the benefit of pumping twice the air in than a sungle turbo of the same size (obviously)
What can help I suppose is by using twin you can make the turbos a bit smaller but still get serious HP but at a lower RPM.

A guy in Townsville reckons he can build a 800hp Turbo Falcon 6cyl engine for around $15k-$17k including a box that can handle that power.....
Youd be lucky to get 450hp from a 5.0L Windsor for that much....

There is no advantage to twin turbos in high Hp applications, the cost of 2 turbos can always get a 1 larger turbo that will flow more air.

Look at the quickest Supras, GTRs and even Mustangs, they are all single Turboed.

firstly, twins or single, if they are sized comparativley, there will be NO noticeable difference in spool OR whatever. that is a myth brought about due to manufacturers using staged twin setups.

just size correctly and if you can get the turbos u need for twin cheaper than singel, do it. same end result.

everyone cries custom intercooler. just get hold of a garret truck IC and have it modified to suit. considering they are utilised on 12+ L trucks that pump more than 20 psi from just of idle, cost 50K + for a rebuild, and the difference in power afforded by a efficiant IC means fuel economy saved by less throttle load (im a truckie, so talking from experience)

"Add forged pistons",
Just as an aside note, it was mentioned in street machine that jake edwards turbo 308 torana was runnign CAST pistons. and a realativley stock bottom end ( stronger rods and bolts) so it isn't always necessary to run forgies, especially in this setup which will be custom = $$$$, and as such it isnt cylnder ressure that causes pistons to fail, its TUNING (eg ping) so tune right

"o-ringed block"
While this can aid in sealing in combustion and etc, having the head gasket as the weak link (relativley speaking) can save you from having a costly rebuild when something has to let go. its so much easier to let the gasket go, than pushing a piston and rod down thru the crank.

" ported head "

apart from match morting and smothing out the ports to remove and obstructions, you dont need to go very far AT all with porting. cause after all, the turbo(S) will be forcing air thru. so as long at the parthways are smooth, its all good.

"6 throttle body setup"
NO WAY would you want this
the extra flow restrictions caused by the 6 throttle plates is un necessary a large single will do the job quite well, and has been proven to see times. why would the jap guy pull the 6 TB setups of the extreme GT-R's if they worked better?

"high flowing injectors"
more like fire hoses

if its going to be a drag only car then a 4" dump pipe straight to the ground is all u need, witha seperate screamer pipe for the wastegate.

when u hit the t8834D ( i think thats amongst the largest) you NEED to goto twins as there simply arent any competition turbos available to go better. hence the cars coming out using twin t72's

i would go forgies as insurance, you might get away with cast but forged pistons are stronger. - we are talking a 8 or 9 second 4.0 here, there will be a lot of stress on all the entire engine, i would go fot the strongest bottom end i could afford!

also see if you can get a crank support machined up instead of just the normal mains caps, it wil help discourage the crank from being pushed out the bottom of the engine when 20 or more psi are shoved down its guts!! (and you will need about 20 or more psi)

and yes i would port the head heaps, not just make the holes bigger but the right shape (shape is more important) and some decent sized valves.

make sure you have a turbo friendly cam (lots of lift but not that much more overlap than stock)

apart from that i agree with maddnez.

what I6 are you using? the 250 crossflow or the 4.0L? either way i think you should investigate running it on straight LPG, it has a very high octane rating and its cheap! apart from that because it is stored as a liquid and turned into a gas it is very cold and so it has intake charge cooling properties, (as well as engine cooling properties) also it is much cheaper to buy and tune pair of gas carbs and get a dizzy recurved than it is to buy and tune a full aftermarket computer.

yes gas is good, its only bad when you try and go dual fuel setup, then it will never work properly, but go for a set of big twin gas carbs on a custom intake and you will be laughing.

you have to go an auto, i dont know where you live but there is a C6 auto in the trader for fairly cheap, rebuilt to handle 1000hp - that should do the trick!

and a 9" diff is a must.

Slick, Quick and Fulliii SIK!!!
Proud TQE Operator
197.4hp at the wheels, 14.505@152.46km/h Tuning in progress...*CLICK TO SEE MY XR6*

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Thanks for all the help so far its just in the planing stages so it may never happen or it may. i hadn't thought of wich engine to use but what r the advantages and disadvantages of the 250 and the newer 4lt (not BA but that would be cool) aslo if does happen it most likely ran LPG

i would suggest the 4.0, from the latest model you can get, i think for strength VS price a ED 4.0 would be the best, but if you can splash out for a EL then better...the EF has coil pack ignition so if you were to use that than you would have to convert to dizzy or get a chip to change the spark advance...im pretty sure that a dizzy from a XD or something fits straight into a 4.0 block, so you just get a rebuilt and recurved XD dizzy and plonk it in, in theory...

if you use the EF or later engine then you would do well to wire it up so it uses the short runner path all the time, this is good for top end which is what you want in a drag car.

Slick, Quick and Fulliii SIK!!!
Proud TQE Operator
197.4hp at the wheels, 14.505@152.46km/h Tuning in progress...*CLICK TO SEE MY XR6*

I can get new Genuine Holden/Ford/Audi/Land Rover/Honda parts cheap, PM me!